I was raised in Columbus, KS about 12 miles north of Cardin, OK and I can remember the Eagle-Picher smelter.The lead and zinc mines around Cardin and Picher were very active during WW2 and up into the mid-50's. You could see the chat piles from miles away and we, jokingly, called them the "Oklahoma Mountains". Now, Picher has been designated a Super Fund Cleanup site because of the lead contamination and the town no longer exists. It was bought by the government and everyone removed except for a few die hard residents. Very sad ending for a small town. Old pictures of it in its heyday show how heavily the area was mined and what a busy town it was.

Those cars appear to be examples of the well-known Difco Side Dump Cars manufactured by the Differential Steel Car Company. The large vertical cylinders can lift and tilt the car body either right or left to unload the lading.